diff --git a/pyplumio/helpers/uid.py b/pyplumio/helpers/uid.py
index cc24e675..1c333d85 100644
--- a/pyplumio/helpers/uid.py
+++ b/pyplumio/helpers/uid.py
@@ -4,9 +4,9 @@
 
 def unpack_uid(message: bytearray, offset: int = 0) -> str:
     """Decode and return a complete UID string."""
-    uid_length = message[offset]
+    length = message[offset]
     offset += 1
-    uid = message[offset : uid_length + offset]
+    uid = message[offset : length + offset]
 
     return _encode_base5(uid + _uid_crc(uid))
 
diff --git a/pyplumio/structures/alerts.py b/pyplumio/structures/alerts.py
index 8d1ed5d0..04c1874d 100644
--- a/pyplumio/structures/alerts.py
+++ b/pyplumio/structures/alerts.py
@@ -26,6 +26,7 @@ def _convert_to_datetime(seconds: int) -> datetime:
     """Convert timestamp to a datetime object."""
 
     def _seconds_to_datetime_args(seconds: int) -> Generator[Any, None, None]:
+        """Convert seconds to a kwarg for a datetime class."""
         intervals: tuple[tuple[str, int, int], ...] = (
             (ATTR_YEAR, 32140800, 2000),  # 60sec * 60min * 24h * 31d * 12m
             (ATTR_MONTH, 2678400, 1),  # 60sec * 60min * 24h * 31d
diff --git a/pyplumio/util.py b/pyplumio/util.py
index 0d668c38..8b626bbf 100644
--- a/pyplumio/util.py
+++ b/pyplumio/util.py
@@ -4,6 +4,7 @@
 import functools
 import struct
 
+# Data type unpackers.
 unpack_float = struct.Struct("<f").unpack
 unpack_char = struct.Struct("<b").unpack
 unpack_short = struct.Struct("<h").unpack
@@ -13,8 +14,6 @@
 unpack_double = struct.Struct("<d").unpack
 unpack_int64 = struct.Struct("<q").unpack
 unpack_uint64 = struct.Struct("<Q").unpack
-pack_header = struct.Struct("<BH4B").pack_into
-unpack_header = struct.Struct("<BH4B").unpack_from
 
 
 def unpack_string(data: bytearray, offset: int = 0) -> str:
@@ -24,6 +23,11 @@ def unpack_string(data: bytearray, offset: int = 0) -> str:
     return data[offset : offset + strlen + 1].decode()
 
 
+# Frame header packer/unpacker.
+pack_header = struct.Struct("<BH4B").pack_into
+unpack_header = struct.Struct("<BH4B").unpack_from
+
+
 def crc(data: bytes) -> int:
     """Return a checksum."""
     return functools.reduce(lambda x, y: x ^ y, data)